#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
#include<vector>
using namespace std;

class Solution {
public:
    vector<int> shuffle(vector<int>& nums, int n)
    {
        vector<int> ret(2 * n);
        int j = 0;
        for (int i = 0; i < n; i++)
        {
            ret[2 * i] = nums[i];
            ret[2 * i + 1] = nums[i + n];
        }
        return ret;
    }
};